Biological Advantages of Porous Hydroxyapatite Scaffold Made by Solid Freeform Fabrication for Bone Tissue Regeneration

Presently, commercially available porous bone substitutes are manufactured by the sacrificial template method, direct foaming method, and polymer replication method (PRM). However, current manufacturing methods provide only the simplest form of the bone scaffold and cannot easily control pore size. Recent developments in medical imaging technology, computer‐aided design, and solid freeform fabrication (SFF), have made it possible to accurately produce porous synthetic bone scaffolds to fit the defected bone shape. Porous scaffolds were fabricated by SFF and PRM for a comparison of physical and mechanical properties of scaffold. The suggested three‐dimensional model has interconnected cubic pores of 500 μm and its calculated porosity is 25%. Whereas hydroxyapatite scaffolds fabricated by SFF had connective macropores, those by PRM formed a closed pore external surface with internally interconnected pores. SFF was supposed to be a proper method for fabricating an interconnected macroporous network. Biocompatibility was confirmed by testing the cytotoxicity, hemolysis, irritation, sensitization, and implantation. In summary, the aim was to verify the safety and efficacy of the scaffolds by biomechanical and biological tests with the hope that this research could promote the feasibility of using the scaffolds as a bone substitute.     

Finite Element Modeling of Stress Distribution in Intervertebral Spacers of Different Surface Geometries

Intervertebral disc spacers using bioactive ceramics have been used to treat degenerative spinal disease. Tooth‐shaped spacers are commonly used to prevent migration, but there is a possibility of fracture when inserted or after insertion. Intervertebral disc spacers with either an isosceles triangle‐shaped tooth (T1) or a right triangle‐shaped tooth (T2) were used as a control group. The design factors for the experimental group were modified to prevent fractures induced by stress concentration, and the surfaces of the spacers were designed as either an isosceles triangle‐shaped valley (V1) or a right triangle‐shaped valley (V2). Linear analysis using finite element model (FEM) was performed, and Von Mises stress distribution was calculated by applying 1000 N of uniformly distributed load. Samples of the V2 design were made with bioactive glass‐ceramics (BGS‐7) and evaluated for compressive strength, fatigue degree, and impact strength. Von Mises stress was highest at the first tooth from the posterior side for the control group and at the center for the experimental group. Compared with the control group, the experimental group showed 18.4% and 82.5% reduction (V1 vs. T1 and V2 vs. T2, respectively) in the maximum stress at the bottom of the valleys. The FEM analysis revealed that the V2 design had the most even load distribution. The V2 samples with bioactive glass‐ceramics were evaluated for compressive strength, and all six samples were not fractured up to 24 000 N. However, the average impact strength was 19.42 kN, suggesting that momentary force caused damage at a lower load than compression with a steady speed. The BGS‐7 intervertebral disc spacer with V2 design was not fractured during the fatigue test at maximum pressure of 8000 N, R ≥10, 5 Hz, and 5 million cycles. These data confirm that the BGS‐7 spacer with the V2 design may be clinically applicable. Collectively, the modified surface geometry of the experimental group significantly lowered Von Mises stress values at the bottom of the valleys, and thus the possibility of fracture by compressive load was greatly reduced. Also, impact during insertion was confirmed to cause fracture more easily, as the impact strength was lower than the compressive strength in the experimental group.     

Leucine‐rich glioma inactivated 3 promotes HaCaT keratinocyte migration

Our finding that human skin expresses leucine‐rich glioma inactivated 3 (LGI3) raises the question of the function of this cytokine in keratinocytes. We have shown that LGI3 stimulates human HaCaT keratinocyte migration without affecting viability or proliferation. Western blot analysis showed that LGI3 induced focal adhesion kinase activation, Akt phosphorylation, and glycogen synthase kinase 3β (GSK3β) phosphorylation in these cells. Using the scratch wound assay and a modified Boyden chamber, we found that LY294002, a selective phosphatidylinositol 3‐kinase inhibitor, and LiCl, a selective GSK3β inhibitor, abolished LGI3‐induced cell migration. We tested β‐catenin levels after LGI3 treatment because the Akt‐GSK3β pathway regulates β‐catenin accumulation, and β‐catenin promotes cell migration. LGI3 treatment increased β‐catenin protein and nuclear localization, whereas LY294002 prevented LGI3‐induced focal adhesion kinase and Akt activation as well as β‐catenin accumulation. Overall, these data suggest that LGI3 stimulates HaCaT cell migration following β‐catenin accumulation through the Akt pathway.     

Periciliary Y-V epicanthoplasty

The epicanthal fold is a semilunar flap of eyelid skin on the medial aspect of the eye. Many surgical techniques have been described to eliminate the epicanthal fold, which is a feature uniquely predominant among the Asian population. However, many surgeons avoid epicanthoplasty because of the fear of visible scar formation. From January of 2002 to April of 2004, 118 patients with medial epicanthal folds underwent epicanthoplasty using a periciliary Y-V advancement procedure for the prevention of visible scar formation. The mean age of the patients was 25.2 years (range, 16 years to 56 years). The median follow-up period was 6 months (range, 2 weeks to 2 years). We performed periciliary Y-V epicanthoplasty only when a patient had wide interepicanthal distance (over 32 mm) or a completely eclipsed lacrimal caruncle.Most of the patients attained satisfactory results, and there were few complications in our cases. Scarring of the medial canthal area has not been a problem with this technique because we designed incisions along the eyelashes and skin-mucosal junctions. We have found that our periciliary Y-V epicanthoplasty is a very reliable and effective method for eliminating the epicanthal fold with minimal scar formation.     

Results of conservative management for consecutive esotropia after intermittent exotropia surgery

Purpose

To examine the clinical course of consecutive esotropia (ET) using conservative management, after intermittent exotropia (IXT) surgery.

Methods

This study included 149 out of 151 consecutive patients with ET after IXT surgery, who were managed conservatively. The clinical course of consecutive ET was examined and the patients were classified into two groups based on the duration of esodeviation: (1) >3 weeks (persistent ET group, n=56) and (2) <3 weeks (transient ET group, n=93). Patient characteristics and treatment outcomes, including the recurrence of exotropia and stereopsis, were compared between the two groups.

Results

All patients with ET were managed with full-time alternate occlusion and/or with a Fresnel prism. In 149 patients out of 151 consecutive patients, 82% of ET disappeared at 12-month follow-up and all at the last follow-up visit (31.4±23.5 months). At the final visit, a recurrence of exotropia of >10 prism dioptres was significantly less frequent in the persistent ET group than in the transient ET group (25% vs 62%, respectively; P=0.01). However, stereopsis outcome was not significantly different between the two groups, and stereopsis change was not affected by age.

Conclusions

By using conservative management only, persistent consecutive ET after IXT surgery disappeared in most cases by the 1-year follow-up visit after surgery. Recurrence of exotropia was significantly less frequent in patients with persistent ET, yet the sensory outcome was not affected by the duration of consecutive ET or age.     

Associations of the infancy body mass index peak with anthropometry and cardiometabolic risk in Mexican adolescents

Background: Early-life growth dynamics are associated with future health. Little is known regarding timing and magnitude of the infancy body mass index (BMI) peak with adiposity and metabolic biomarkers during adolescence.

Aim: To examine associations of the infancy BMI peak with anthropometry and cardiometabolic risk during peripuberty.

Methods: Among 163 ELEMENT participants, this study estimated age and magnitude of the infancy BMI peak from eight anthropometric measurements from birth–36?months using Newton’s Growth Models, an acceleration-based process model. Associations were examined of the infancy milestones with anthropometry and cardiometabolic risk at 8–14?years using linear regression models that accounted for maternal calcium supplementation and age; child’s birthweight, sex, and age; and the other infancy milestone.

Results: Median age at the infancy BMI peak was 9.6?months, and median peak BMI was 16.5?kg/m². Later age and larger magnitude of the peak predicted higher BMI z-score, waist circumference, and skinfold thicknesses; i.e. each 1?month of age at peak and each 1?kg/m² of peak BMI corresponded with 0.04 (0.01–0.07) and 0.33 (0.17–0.48) units of higher BMI z-score, respectively. Later age at peak was also a determinant of worse glycaemia and higher blood pressure.

Conclusion: Later age and larger magnitude of the infancy BMI peak are associated with higher adiposity at 8–14?years of age. Later age but not magnitude of the BMI peak are related to a worse cardiometabolic profile during peripuberty.     

Treatment of Post-Ablation Bronchopleural Fistula Using Percutaneous Synthetic Hydrogel Surgical Sealant: Initial Experience of Safety and Efficacy

CardioVascular and Interventional Radiology - Purpose Bronchopleural fistula is a rare but serious complication of lung ablation, as it is difficult to treat and is associated with a high mortality...